Fast-food “swamps” linked to high rates of obesity, when healthier choices crowded out: Ontario study

People living in areas with high numbers of fast-food restaurants and few healthy alternatives are more likely to experience obesity, says a new study from the Institute for Clinical Evaluative Sciences (ICES) and St. Michael’s Hospital in Toronto, Canada.

“Recent studies out of the US and elsewhere have demonstrated the public health risks of what are being called ‘food swamps,’ which are areas with an overabundance of high-energy, low nutrient foods,” says Jane Polsky, the study’s lead researcher who is a PhD student with the University of Toronto Dalla Lana School of Public Health and St. Michael's Hospital. “However, our study is the first to take a closer look at the relative availability of fast-food options compared to healthier alternatives within a walk from home, and whether it matters more in areas with low or high volume of restaurants.”

To be published next month in the journal Preventive Medicine, the study examined health data for approximately 10,000 adults living in four cities in southern Ontario (Toronto, Brampton, Mississauga and Hamilton) who participated in the Canadian Community Health Survey between 2005 and 2010. Taking into account such demographic factors as age, sex, marital status, household income, race, immigration status and education, the researchers looked at the participants’ weight measurements including obesity and body mass index (BMI). They also examined the walkability of the participants’ neighbourhoods within a 10-minute walk, looking at factors such as population density, street connectivity and the availability of services and amenities. They then looked at the number of fast-food, full-service and other restaurants within the walkable area and measured the proportion of fast-food outlets relative to all restaurants.

They found that people are as much as 2.5 times more likely to experience obesity when their neighbourhoods have a disproportionally high volume of fast-food outlets and few healthier choices. This was compared to residents who also lived near many fast-food outlets but had more healthful choices nearby. 

“Our results show that having restaurant options that offer healthier alternatives to fast-food – for example cafes, sit-down restaurants or coffee shops – is important for lower body weight, and this is particularly important for residents of areas with a higher number of fast-food restaurants,” says Polsky. “The double whammy of having high numbers of fast-food restaurants with few healthier alternatives is associated with the highest levels of excess body weight, even in highly walkable areas.”

“Given the continuing epidemic of obesity, policymakers are increasingly looking for levers within the local retail food environment as a means of promoting healthy weights,” says Gillian Booth, senior researcher on the paper who is a scientist at ICES and the Li Ka Shing Knowledge Institute at St. Michael’s Hospital. “This study suggests that along with encouraging neighbourhood walkability and ready availability of healthy food, policies that achieve a better balance of restaurant types with more alternatives to fast food could go much farther in encouraging healthy weights.”

“Absolute and relative densities of fast-food versus other restaurants in relation to weight status: does restaurant mix matter?” will be published in the January issue of the journal Preventive Medicine and is now available online.

Author block: Jane Y Polsky, Rahim Moineddin, James R Dunn, Richard H Glazier, Gillian L Booth.

The Institute for Clinical Evaluative Sciences (ICES) is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy. For the latest ICES news, follow us on Twitter: @ICESOntario

St. Michael’s Hospital provides compassionate care to all who enter its doors. The hospital also provides outstanding medical education to future healthcare professionals in more than 23 academic disciplines. Critical care and trauma, heart disease, neurosurgery, diabetes, cancer care, and care of the homeless are among the Hospital’s recognized areas of expertise. Through the Keenan Research Centre and the Li Ka Shing International Healthcare Education Center, which make up the Li Ka Shing Knowledge Institute, research and education at St. Michael’s Hospital are recognized and make an impact around the world. Founded in 1892, the hospital is fully affiliated with the University of Toronto. www.stmichaelshospital.com

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